In children, unrecognized Sleep Disordered Breathing (SDB) may significantly contribute to learning and behavioral problems, and predispose to the development of cardiovascular problems. Adolescents may be predisposed to SDB because of weight gain or sleep restriction. However, the prevalence and impact of SDB in teenagers have not been systematically studied. Over the last 3 years, we have studied a unique cohort of 907 children (41% minority), ages 8-11, many who have been under observation since age 3 years. Our physiological and neuropsychological measurements provide fundamental data regarding the prevalence of SDB and risk factors for SDB in pre-pubertal children. Preliminary analyses indicate that children with snoring or SDB perform more poorly on a number of tests of cognitive function, and have more behavioral morbidity than do other children. We propose extending this study to assess the morbidity of SDB in adolescents (ages 13-16 years), addressing the extent to which SDB in childhood impacts behavior, cognitive functions, and neuro-endocrine responses important in the pathogenesis of cardiovascular disease or diabetes. We hypothesize that the effects of sleep fragmentation, reduced slow wave sleep and sleep-associated intermittent hypoxemia may lead to deficits in executive functions, insulin sensitivity, and abnormalities in the somatotropic axis. We also will quantify the impact of putative risk factors on adolescent SDB, including race/ethnicity, overweight, small pharyngeal size, prematurity, familial SDB, and SDB at ages 8-11 years. For efficiency, we will perform stratified sampling of 250 children from this cohort (125 with habitual snoring or sleep apnea at ages 8-11 yrs., and 125 children randomly selected from the remaining cohort, frequency matched by gender, term, and race). Children will undergo overnight state-of-the-art-sleep monitoring, a glucose tolerance test, acoustic rhino-pharnygometry, anthropometry, spirometry, blood pressure, and a focused battery of neuropsychological and behavioral assessments. Specimens for biomarkers and potential confounders (e.g, measures of puberty and thyroid status) will be collected, some both before and after sleep. First-degree relatives also will undergo sleep studies and relatives and children will have DNA collected for future studies. This proposal provides the opportunity to characterize the prevalence and morbidity of SDB in a well-characterized population-based sample, including a large proportion of minority and preterm adolescents who appeared to be at high risk for SDB at younger ages, and may be at increased risk for SDB-associated chronic morbidities, and poorer cognitive development. Comprehensive data collection and statistical analyses will permit identification of potential pathophysiological mechanisms for, and effects of, SDB.